The Infiniband® network includes nodes that communicate through a channel-based switched fabric (Infiniband® is a registered trademark of Infiniband Trade Association, located in Beaverton, Oreg.). For example, the nodes may be a host, an input/output subsystem, or a router which connects to another network. The switched fabric is made of a collection of switches, routers, and/or links that connect a set of channel adapters. The channel adapters form an interface between the switched fabric and the nodes. The channel adapter of the host is referred to as a host channel adapter. The channel adapter of an I/O subsystem is referred to as a target channel adapter.
In Infiniband®, two processes communicate using a queue pair. A queue pair (QP) includes a send queue and a receive queue. Specifically, in order for a process to send a message to another process, the process posts the message to the send queue. The host channel adapter sends the message in the form of packets to the channel adapter having the receive queue. Each packet that is sent may include a packet sequence number. Logic associated with the receive queue ensures that packets are processed in a particular order using the packet sequence number.
Infiniband® supports operations such as multicast packet replication. Specifically, multicast packet replication requires that a copy of a packet be delivered to multiple QPs on the host system. Common solutions to this use software replication. Specifically, all incoming multicast packets are redirected to a single QP on a single virtual machine (VM). Host software on that VM is responsible for implementing replication to all VMs. Each VM is then responsible for replicating a packet to each group member QP.